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Title of Thesis
Immunological Manifestations of toxicants in Cyprinus carpio (common
carp) & Oncorhynchus mykiss (rainbow trout) |
Author(s)
Asma Karim |
Institute/University/Department Details
GC University, Lahore, Pakistan |
Session
2009 |
Subject
Zoology |
Number of Pages
174 |
Keywords (Extracted from title, table of contents and abstract of thesis)
pathogens, Oncorhynchus mykiss, humoral, cyprinus carpio, proliferative |
Abstract
Organisms have
naturally build defense mechanisms against infections and diseases
caused by pathogens. This system known as immune system comprises of
innate immunity and adaptive immunity. Innate immunity is non
specific and produces a quick response to the invading pathogens.
Macrophages play central role in innate immunity, also called
natural immunity. The other part of immunity is rather specific and
it takes some time to show its response, this type of immunity is
called adaptive immunity. Adaptive immunity can be either T cell
mediated or B cell mediated in response to intra cellular or extra
cellular pathogens respectively. When it is T cell mediated it will
lead to the secretion of cytokines including interferon along with
other substances, which help to fight intra cellular pathogens
especially viruses by activating natural killer cells and
macrophages. B cell mediated immune system leads to production of
antibodies in response to extra cellular pathogens in blood or other
body fluids. The whole immune system including innate immunity and
adaptive immunity mediated by both T cell and B cell are not
separate from each other but rather linked with each other and
activating each other against foreign invaders. For example
macrophages activate T cells, T cells activate macrophages, B cells
and other T cells. Purpose of present study is to know about the
adaptive immune system of two farm fishes, rainbow trout and common
carp which are main source of protein in Pakistan. This study will
provide a guide line to improve the immune system of farm fishes so
that they can be resistant to diseases. This will ultimately benefit
the human beings as they will get more Omega 3 rich protein, which
is good for the over all health of human beings. In the present work
both cellular and humoral aspects of adaptive immune system mediated
by T and B lymphocytes were studied. Two teleost fishes rainbow
trout Oncorhynchus mykiss (Scottish farm fish) and common carp
Cyprinus carpio (Pakistani farm fish) were taken as experimental
animals. Immune genes which regulate interferon production as a
cellular immune response to viruses or other intracellular
pathogens, were
studied in rainbow trout Oncorhynchus mykiss, B cell mediated immune
system leading to production of antibodies was studied in common
carp Cyprinus carpio. It was found that production of interferon is
regulated by immune genes known as interferon regulatory factor (IRF)
genes. These IRF genes are 10 in number and are named as IRF1, IRF2,
IRF3, IRF4, IRF5, IRF6, IRF7, IRF8, IRF9& IRF10 and altogether form
IRF family. IRF genes have been sequenced so far in many species
including human beings. In rainbow trout IRF1, 2, 3&7 have been
sequenced till to date. In present project work was done on
remaining members of the IRF family. During the project two full
length genes IRF 4& IRF8 were sequenced along with partial sequences
of IRF 5& IRF10. It was found that certain toxicants like Poly I: C
trigger IRF genes to produce positive immune response by secreting
cytokines like interferon. Poly I: C (Polyinosinic: polycytidylic
acid) is a synthetic double-stranded RNA that is used experimentally
to model viral infections in vivo. IRF4 gene was expressed in
rainbow trout spleen cells treated with Poly I: C for 4 hours. IRF 8
gene was expressed in spleen and head kidney cells. After multiple
alignments of genes it was found that the gene structure of IRF4&8
genes found in rainbow trout had close structural resemblance with
IRF4&8 genes found in other fish like zebra fish or even in mammals
like human being and mouse. IRF4 &IRF8 play an important role in
maturation of B and T lymphocytes. The other aspect of adaptive
immune system, B cell mediated or humoral immunity was studied in
common carp Cyprinus carpio. It was found that humoral antibodies
are detected in serum of fish after secondary immunization with
particulate antigen SRBC (sheep red blood cells). Proliferative
response in lymphoid tissues especially in spleen and kidney was
high while there was less response in liver. HGG localization in
these tissues was studied by using fluorescent labeled antibodies
against HGG. Farm fish in Pakistan are built in agricultural lands
and so these fish are in contact with the pesticides used on crops
through water run off to these fish farms. It was found during
experimental work that toxicants like pesticides affect the immune
system of common carp by suppressing the production of antibodies.
Histological studies were also conducted which showed that besides
affecting immune system of fish, these pesticides also have harmful
affects on lymphoid tissues of fish and also on immune system of
fish.
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